Hi Kim
Talcum powder works very well to remove the surface soil, cover the marked area and leave for few minutes then vacuum away with a crevice tool a few centimeters form the carpet, avoid contact if you can, then I would suggest removal using a micro splitter such as Dynax no8, No3 spotter or eco spotter, Solvall, or Prochems Ultra Renovate indirectly applied using terry towel or similar.
Best regards Nick